Abstracts (first author)

Talk

Tracing the origins of domestication in the wine yeast Saccharomyces cerevisiae

Author(s): Almeida PM, Bensasson D, Sampaio JP

Summary:

The domestication of plants and animals represents a milestone in human history because it triggered critical transitions of human civilizations. Recent studies suggest that the yeast Saccharomyces cerevisiae, which is used nowadays in the fermentation of wine and other alcoholic beverages worldwide, illustrates the case of a microbe that has been also domesticated. However, the vast wealth of knowledge that has been gathered for the understanding of crop and livestock domestication contrasts markedly with our ignorance on microbe domestication. Recent advances in sequencing technology are providing novel opportunities for microbe population and evolutionary studies through the availability of genome-wide molecular markers that allow an unprecedented fine scale resolution of population dynamics and organismic evolution. Here, we have surveyed sequence variation using whole-genome sequencing in a dataset of S. cerevisiae strains that were isolated from natural environments (putative wild populations) and human-associated niches (putative domesticated populations), from different geographic regions at a global scale. The hypothesis to be tested is that the wild ancestors of wine yeasts are found close the main center of origin and spread of winemaking. We found a distinct and previously undescribed phylogenetic lineage of S. cerevisiae that is the closest known wild relative to the wine yeast group and is distributed along the Mediterranean basin. We propose that these two lineages diverged only recently, a view that is reinforced by the proportion of shared alleles and the low number of fixed differences between them. We discuss the significance of an excess of rare variants in the wine group relative to wild strains. The work described here seeks to provide new insights into the history of domestication and improve our knowledge on the ecology of this important microbe.